/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.flink.metrics.util;

import org.apache.flink.metrics.reporter.MetricReporterFactory;

import java.util.ServiceLoader;
import java.util.Set;
import java.util.stream.Collectors;
import java.util.stream.StreamSupport;

import static org.hamcrest.Matchers.hasItem;
import static org.junit.Assert.assertThat;

/**
 * Test utils for metric reporters.
 */
public class MetricReporterTestUtils {

	/**
	 * Verifies that the given {@link MetricReporterFactory} class can be loaded by the {@link ServiceLoader}.
	 *
	 * <p>Essentially, this verifies that the {@code META-INF/services/org.apache.flink.metrics.reporter.MetricReporterFactory}
	 * file exists and contains the expected factory class references.
	 *
	 * @param clazz class to load
	 */
	public static void testMetricReporterSetupViaSPI(final Class<? extends MetricReporterFactory> clazz) {
		final Set<Class<? extends MetricReporterFactory>> loadedFactories = StreamSupport
			.stream(ServiceLoader.load(MetricReporterFactory.class).spliterator(), false)
			.map(MetricReporterFactory::getClass)
			.collect(Collectors.toSet());
		assertThat(loadedFactories , hasItem(clazz));
	}
}
